Automatic clamp-opener throw-outs



Feb. 11, 1958 w. J. EDWARDS AUTOMATIC CLAMP-OPENER THROW-OUTS 4 Sheets-Sheet 1 Filed March 8, 1955 INVENTOR Wm H 4 E W n x wN m 2. 8. we. 2. W 8 r h 2 g 2. u v Q a: u 0 NN mwmw w w 0m v mv t mv ww M 9 m mm 2 5w B q a William J. Edwards Feb. 11, 1958 Filed March 8, 1955 W. J. EDWARDS AUTOMATIC CLAMP-OPENER THROW-OUTS 4 Sheets-Sheet 2 WITNESS INVENTOR William J Edwards Feb. 11, 1958 w. J. EDWARDS 2,822,772

AUTOMATIC CLAMP-OPENER THROW-OUTS Filed March 8, 1955 4 Sheets-Sheet 3 INVENTOR v William J. Edwards WITNESS WMQW ' AT ORNEY Feb. 11, 1958 w. J. EDWARDS AUTOMATIC CLAMP-OPENER THROW-OUTS 4 Sheets-Sheet 4 Filed March 8, 1955 INVENTOR William J. Edwards Fig.5

WITNESS MMQW e 2,822,772 1 Patented. Feb. 11,. 195.8

AUTOMATIC CLAMP-OPENER THROW-OUTS.

William J. Edwards, Stratford, C'onn;, assignor to The Singer Manufacturing Company, Elizabeth, N. 3., a corp oration of New Jersey Application March 8, 1955, Serial N 0. 492,921

13' Claims. (Cl; III-110) This invention relates to cyclically operatedsewing machines and more particularly to mechanisms for'opena ing thework-holding cl'ampof a sewing machine.

It is an object of this invention toprovideanovel-and efiicient throw-out device for an automatic clamp-openingmechanism of the type which derives its motivation from. the actuating mechanism of the sewing machine.

It is also an object to provide a-means in a cyclically operated sewing'machine for selectively varying-theduration of theeoasting; period of the sewing machine at the termination of each cycle of operation.

Still another'object of this invention is tov provide a throw-out device for an automatic clamp-opener. of a cyclically operated sewing machine, which device also serves toeffect an increase; in the coasting period-of. the sewing. machine when the clamp-opener is thrown out.

With the above, and additional objects and advantages in View as will'hereinafter appear, this invention. comprises the devices, combinations, and arrangements of parts hereinafter described and illustrated inv the accom. panying. drawings of a preferred embodiment thereof in which:

Fig. 1' is a side elevational view of a sewing machine having the side cover-plate of the machineframe removed and portions of. the: machine bed broken. away and illustrated in cross-section to expose: the invention applied thereto;

Fig. 2 represents .an enlarged: vertical cross sectionof a portion of the sewing machine taken substantially along line 2-2 of Fig. 1;

Fig. 3'isa bottom view of a sewing machine of Fig. 1;

Fig. 4 represents an enlarged elevational view of portions of the clamp-opening mechanism, as illustrated in Fig. 1 with additional parts being broken away andillustrated in cross-section;

Fig. 5 represents a horizontal cross-section of a. portion of the automatic clamp-opener throw-out mechanism taken substantially along line 5-5 of Fig. 4, but with theparts. being illustrated in proper position for nonautomatic or operator influenced operation of the clampopening mechanism;

Fig. 5A represents a horizontal cross-section similar to Fig. 5, but with the parts being illustrated in proper posit tion for automatic operation of the clamp-opening mechanism;

Fig. 6 is a fragment of the bottom view of. the sewing machine illustrated in Fig. 3, showing the stop-motion latching mechanism in a position corresponding to nonautomatic or operator influenced operation of the clampopening mechanism; and

Fig. 6A is a view similar to Fig. 6 but showing the stopmotion latching mechanism in a position corresponding to automatic operation of the clamp-opening mechanism.

In sewing machines which are specifically adapted to secure an article to a body fabric as, for instance, in the button sewing machine illustrated in the accompanying portion of the bed of the drawings, a work clamp, indicated generally at 11, is em. ployed. The work clamp is provided with a lower jaw portion 12- and-an upper button-gripping jaw portion 13 which is. pivoted at 1 4" to the lower jaw so as to provide ahinged and readily releasable clampfor the body fabric andv a. means for gripping and locating; the button with respect to the fabrics The s in machin u t ated in the drawings rreterably of a .conventi nal type-for this; class of article: at;- taching operationrin. that the machine frame comprises ed-15 meu tedmpcn a s base. 16, and a: standa 17 from which a braeket arm 18, extends in vertically spaced' relat p to the bed. A main drive shaft 19*iourn-aied' he: bed is:;a1= ranged,. as,is, well knownina the art; {Udfiifiefhglhi aaneedIe-ZO and-a-looper21 which'isrcomplemental to: he needle in. the formation. of stitches. AlsoidIiven-by-tlre: main drive shaftzl-Q is av cam. shaft 22 which; is: journaled: vertically in, the machine. frame and has securedfor rotationtherewith a first pattern cam2-3 disposed within the; bracket. arm 18 and. tracked by a follower 24 which serves to jog the needle. A' second pattern cams2frf secured-tothe cam shaft beneath the bed and is tracked from:v above by a cam follower 26 which serves to! impart jogging movements to the l-ooper eomplemcntal to the jogging movements of the needle, and" is trackedZfrorrt below.- by a camfollower 27 which serves to shift: the: work clamp bodily along the machine bed: The; specific arrangement of cam followers is well'yknown in. the artand serves to provide a machine in which. the. needlea-nd the looper are jogged to. stitch alternately through a first pair .of holes in a button and in whichthe work clamp is shifted to present a second pair of holes; to theistitch-formi'ng instrumentalities. The upper jaw portion 13' of the workclamp is nor mal-ly biased downwardly into closed work gripping relation with the lower jaw portion by means of a presserbar 29 endWise slidabl'e in thebracket arm. The lower extremity of the pres'senbar is disposed in engagement Withthe-upper jaw portion and is biased downwardlyby a. coil. spring 30' sea-ted against an adjusting screw 31 accessible from the top of the bracket arm for changing the spring pressure operative to; maintain the work clamp in closed -p osition.

In order to effect opening of the Work clamp in opposi: tion to the coil spring 30, a link 32 is arranged between the upper jaw 13- of the clamp and a rock arm 33 of a clamp-opening rock shaft 34 journaled in the; bracket arm. The clamp-opening rock shaft is controlled by means of a push rod 35 journaled vertically in bearing bushings 36, 36 inthe machine standard. A rock arm 37 and a link 38 serve tointerconnect the push rod 35 with the clamp-openingrock shaft 34.

As is customary in article attaching sewing machines of the type disclosed in thedrawings, stop-motion mechanism is provided for rendering the operation thereof cyclic. In the drawings, a stop-motion mechanifi is illustrated of the type disclosed in the copendingpatent application of R. 13. Sweet and W. 1. Edwards, Serial 1 2 filed, Ma .0 hi rrefere c may behad for a. detailed description thereof. The stop: motion mechanism Wili be described here onlyto theex tent necessary for a complete understandingof the -pres. ent invention.

The motion necessary to drive the sewing machine. is delivered from any conventional source of power by means of a V belt 39 which engages a two-partseparable pulley havingv an inner pulley portion 40, which is fixed for rotation with the main drive shaft 19, and an outer pulley portion 41, which is freely journaled on the main drive shaft and which is free to move axially thereof. The loose outer pulley portion 41 may be urged inwardly so as to compress and pinch the side of the V belt frictionally against the fast inner pulley portion so that the belt will drive the sewing machine main shaft. Similarly, when the force urging the loose outer pulley portion inwardly is discontinued, the V belt will ride idly upon the outer loose pulley portion and the transmission of power to the sewing machine will be interrupted. In order to control the loose outer pulley portion 41, a swinging stopmotion frame 42 is pivoted at 43 to lugs 44 extending outwardly from the sewing machine standard. The stopmotion frame depends from the pivot 43 and has fixed thereto a substantially horizontal operating arm 45. The frame 42 loosely embraces the maindrive shaft 19 and terminates in a downwardly and laterally extending arm 46 which, as will be described in detail later, serves to control the automatic clamp-opening mechanism. Riveted to the stop-motion frame near the pivot 43 is a relatively flat spring member 47 which extends downwardly and into axial engagement with an antifriction thrust bearing ball 48 journaled at the outer extremity of the loose outer pulley portion. The spring member 417 is embraced and stiffened by a support member 49 which extends from the swinging frame. Movement of the swinging frame will thus serve to control the transmission of power to the sewing machine.

The swinging frame 42 also serves to bring the sewing machine to a definite predetermined at-rest position and to lock the machine in this position until initiation of a succeeding cycle of operation. To this end, a rod 50 is journaled for endwise movement vertically in a lug 51 formed to extend from the stop-motion frame. The rod is resiliently centered with respect to the lug by means of coil springs 52 and 53 and is provided at its lower extremity with a stop block 54 which cooperates with a notched stop cam formed on the sub 55 of the fast inner pulley portion 40. Thus, after the stop-motion frame is turned so that the loose pulley portion becomes free on the main drive shaft and the power to the sewing machine is discontinued, further movement of the stop-motion frame will bring the stop block into engagement with the notched stop cam and the machine will be brought to a cushioned stop in a definite position determined by the position of the stop cam on the main drive shaft.

The automatic clamp-opening mechanism, as best illustrated in Figs. 1, 2 and 3, is patterned after that forming the subject of the copending U. S. patent application of R. D. Sweet and W. J. Edwards, Serial No. 466,034, filed November 1, 1954, to which reference may be had for a complete description thereof. The automatic clampopening mechanism will now be described to the extent necessary for a clear understanding of the present invention.

Disposed to engage the depending free end of the clamp opening push rod 35 is the horizontal arm 56 of a bell crank lever 57 fast upon a stud shaft 58 which is journaled for both turning and sliding movements in a boss 59 formed in the bed 15. A vertical follower arm 60 of the bell crank is urged by a coil spring 61 into engagement with a clamp-opening cam member 62 which is fast on the sewing machine main drive shaft 19. The cam member 62 is formed with a substantially cylindrical hub portion 63 from one side of which rises a cam lobe 64. A coil spring 65 restrained between the bed and an enlarged head 66 formed on the stud shaft 58 serves to bias the stud shaft and the bell crank 57 fixed thereto to the right, as viewed in Fig. 1, and into a position determined by a stop screw 67 threaded into the lateral arm 46 of the stop-motion controlling frame 42. During operation of the machine, the bell crank 57 is shifted to the left, as viewed in Figs. 1 and 3, by the lateral arm 46 and the vertical follower arm 60 of the bell crank is maintained in engagement with the substantially cylindrical hub portion 53 of the cam 62. When the stop-motion frame is released and moves into the stopped position of Figs. 1, 2 and 3, the bell crank 57 is free to move to "nit; right in a position in which the follower arm 60 will be acted upon by the cam lobe 64 to actuate the push rod 35 and open the work clamp.

Carried above the bed 15 within the standard and as illustrated in Fig. 5A, is a latch lever 68 urged by a coil spring 69 toward the push rod 35. The push rod is notched, as at 70, so as to accommodate the latch lever 68 when the push rod is shifted to open the clamp. The latch lever 68, therefore, assumes from the bell crank 57 the burden of the clamp-closing spring 30 as well as a return spring 71 on the push rod 35, thus freeing the clamp-opening bell crank 57 for comparatively effortless axial shifting movement upon initiation of a succeeding cycle of operation. A trip finger 72 fixed to depend from the actuating arm 45 of the stop-motion frame 42 is disposed to engage an upturned lug 73 on the latch never 63 to shift the lever out of the notch 70 in the push rod as a succeeding cycle of stitches is initiated.

The present invention provides a device for throwing out of operation the automatic clamp-opening mechanism so that, whenever it is so desired, the work clamp may be opened and closed by manual or other operator influenced means.

The throwout mechanism, which is best illustrated in its entirety in Figs. 2 and 4, is operated by a lever 75 secured by a pivot screw 76 atop the machine bed and having an operating handle 77. A pair of hell crank levers 78 and 79 are pivoted inside the machine bed by pivot screws 80 and 81, respectively, and are interconnected by means of a pin 82 carried by the lever 79 and a pin-accommodating slot 83 formed in the lever 78. An upstanding arm 84 of the lever 78 is bifurcated and disposed to extend through an opening 85 in the bed and to embrace the throw-out lever 75, while the depending arm 86 of the lever 79 is disposed within a transverse slot 87 formed in the boss 59 in which the stud shaft 58 for the automatic clamp-opening bell crank is journaled. The stud shaft 58 is formed with an annular groove 88 disposed to occupy a position in alignment with the transverse slot 87 in the boss when the sewing machine is operating and the clamp-opening bell crank 57 is shifted out of operative position in the path of the clamp-opening cam lobe 64. The depending arm 86 of the lever 79 may be shifted in response to movement of the operating handle 77 to a position within the annular groove 88 of the stud shaft 58 in order to latch the clamp-opening bell crank into this inoperative position.

In Fig. 5, the lever 75 is illustrated in position for manual' operation of the clamp-opening linkage, while Fig. 5A represents the same view with the parts being disposed in positions corresponding to automatic operation of the clamp-opening mechanism.

The lever 75 is joined by an arm 89 which is adapted to engage the latch lever 68. As illustrated in Fig. 5, when the parts are positioned for manual opening of the clamp, the arm 89 holds the latch lever 68 out of engagement with the notch '70 of the push rod 35. The work clamp, therefore, will not be latched in open position when the automatic clamp-opening mechanism is thrown out of operation and, consequently, the operator will have direct control over both the opening and the closing of the work clamp.

. As bestillustratcd in Figs. 2 and 3, the mechanism by which the work clamps may be controlled under the influence of .the operator comprises a bell crank 91 which is pivoted on a bracket 92 carried by the sub-base 16 of the machine. The bell crank 91 is formed with an offset finger 93 which is disposed to underlie the horizontal arm 56 of the automatic clamp-lifting bell crank lever 57, and is provided with a pull chain 94 which may be connected with any suitably arranged treadle or knee shifter. A- spring 95 is associated with the bell crank 91 and serves to bias the offset finger 93 into an extreme lowered position against the sub-base 16 so that when the bell crank 91 is idle, the offset finger 93 will not number of stitches have been made, as best illustratedin Figs. 1 and 4, comprises a link 97 pivotedto the actuated arm 45 of the stop-motion frame and to a slide rod 98 which is journaled vertically in the machine bed. A bell crank 99 carried by the sub-base 16 of the machine is adapted to be operated by the machine operator by means of :a pull chain 1'00, and bears beneath the slide rod 98 so as to shift the stop-motion frame in a clockwise direction, as viewed in Pi 1, in opposition to a coil spring 101 between the machine standard andthe stop-motion frame to initiate a cycle of stitches.

The stop-motion frame is maintained in running position during the cycle of stitching operation by means of a latch arrangement between a sleeve 102 which loosely embraces the slide rod 98 and a latch lever 103. The

sleeve 102 is tapped to receive set screws such as that illustrated at 104 which project into an annular groove 105 formed in the slide rod, thereby to lock the sleeve for axial movement with the slide rod while providing for freedom from rotational movement ofthe sleeve with respect to the slide rod.

The lower extremity of the sleeve 102 is formed with stepped substantially concentric portions 106 and 107 defining shoulders 103 and 109, respectively, in substantially parallel planes spaced axially along the sleeve 102. The end portion 1070f the sleeve is notched, as at 111, which serves, as is best illustrated in Figs. 6 and 6A, to provide a widened portion 108A of the shoulder 108 and a correspondingly narrowed portion 109A of the 'shoulder 109.

The latch lever 103 is fast on a rock'shaft 112 journaled transversely of the machine bed 15 andis formed with a substantially vertical arm 113 terminating'in a latch finger 114 which is movable readily with respect to the slide rod 98 in a path traversing the shoulders 108 and 109 of "the sleeve 102. A substantially horizontal arm 1 15 of the latch lever 103 is formed with a trip finger 116 disposed for engagement with a 'cam plate 117 secured by screws 1'18'1'18 to the periphery of-the pattern cam 25 within the machine bed. A coil spring 119 urges the latch lever 103 in a clockwise direction.

The bottom edge of the cam plate 117 isstepped to provide three cam surfaces 120, 121 and 122 disposed in parallel planes which are evenly spaced axially with respect to the pattern cam 25. In Fig. 1, the sewing machine is illustrated in stopped position andthe trip finger 116 is in engagement with the cam surface 120, in which position the latch finger 114 is shifted beyond'the periph- Lery of the concentric portion 106 of the sleeve 102, thus freeing'the sleeve 102, the slide rod 98 and the stop- "m'otion'frame for movement in response to'the coil spring 101 intothe stopped position. -ing=machine upon a-succeeding cycle of stitches, the sleeve 102 and the slide rod 98 are raised -'by manual actuation of the bell crank 99. As'the maindrive shaft and, consequently, the pattern cam shaft 22 begin toaturn, the cam plate 117 moves toward the right, as viewedin Fig. 1, and the cam surface 120 is shifted out of engage- In order to start thesewment with the trip finger 116, thus releasing the latch slever -'3for movement in response to spring 119 to a position in whichthe latch finger underlies the shoulder 109 of the sleeve "102, thus locking the sewingmachine actuating mechanism in running position for one cycle of rotation of the pattern cam 25, i. e., until thecam Since the cam plate 117 is provided withstepped-cam -*surfaces 120, 121 and 122, the latch lever.103,at the completion of each cycle of machine operation, will be shifted in threestages to release the sleeve-102 and;the

.ing machine.

sliderod 98 to stop the machine. As statedabove, the

latch-finger 114 .of the latch lever is disposed in engagement with the shoulder 109 during operation of the sew- Asthelatch finger:114 is shifted outwardly away from the slide rod98, it moves beyond the shoulder '109 bringing the shoulder 108 into engagement .With the latch finger and thus partially releasing the sleeve -102 andthe slide rod 98 .so as to discontinue -;the.transmission of power to the sewing machine. The sewing machine then coasts .until the latch lever 103 i s shifted an addi- .tional amount to the position .as shown, for instance, Fig. 4 in which the latch finger is movedoutwardly beyond .the shoulder 108 of thesleeve 1102 thus completely freebraces a pin 124 extending radially from the sleeve 102 while it is coasting to a stopped position. v; rnatic clamp-opening mechanism is rendered inoperative, it is advantageous to increase the coasting period so as so that as the throwout lever is turned from a position corresponding to manual operation of the clamp opener, as shown in Fig. :5. to a pos ti co resp to automatic clamp opening, as shown in Fig. 5A, the sleeve 102 will beturned from a position in which the notch 111 overlies the path of movement of the latchfinger 114, as shown in-Fig. 6, to aposition in which the notch 111 is disposed entirely atone side of the path of movement of the latch linger, as illustrated in Fig. 6A.

The stepped cam surfaces 120, 121 and 122 and the angularly adjustable sleeve 102 provide a means for varying the period during whichthe machine will coast, i. e., the time increment between that at which the transmission of power is interrupted ,and that at which the machine reaches its definite stopped .pqsition. Of the many possible advantages of a rr ge ans for varying the coasting p iod of a se n machine .0116 llustra i t p ferred embodiment of the drawings is that the machine may thereby be adjusted to operate smoothlyand at a clamp-opening mechanism utilizes for its operation the momentum of'the sewing machine actuating mechanism When the autoto dissipate in coasting the added increment of kinetic energy no longer drawn off by the clamp opener. ,By lengthening the coasting periodunderthese circumstances, strain on the stop-motion mechanism ordinarily cushioned by the clamp-opening mechanism, is correspondingly reduced.

Operationof the means for varying thecoasting period is indicated in Figs. 6; and 6A, in both of which thetrip finger 116 of the latch lever 103 is disposed in engagement with the first step 122 of the cam plate 117. gIn Fig. 6 which illustrates the position ofthesleeve 10 2 corresponding to manual operation of ;the clamp opener,-the notch 111 is disposed so ;.as to be intersected by the path of the latch finger 114 of the latch lever ;1 03. Latch finger 114 thus traverses the narrow portion 109A of the shoulder 109 so that the increment of latch movement occasioned by the first cam surfaces 122 causes the finger 114 to release the shoulder 109 and take up a positionin engagement with the widened portion 108A of. the shoulder 108 in which position of parts the transmissionof powerto the sewing machine will be interrupted. and the machine will coast. As the succeeding cam surface 121 engages the trip finger 116, the latch finger 114 merely moves radially along the widened portion 108A of shoulder 108 and the coasting continues until the cam surface shifts the latch finger 114 completely beyond the sleeve 102, as illustrated in Fig. 4.

In Fig.. 6A, the parts are illustrated in position corresponding to automatic operation of the clamp-opener. The notch 111 of shoulder .109 is turned out of. the path .of the latch: finger v1L4. so that the .normal width of the ease-p72 shoulder 109 is presented to the latch finger. With this position of parts, engagement of the initial step 122 of the cam plate 117 with the trip finger 116 merely moves the latch finger 114 radially along the shoulder 109 to the position illustrated in Fig. 6A and does not interrupt transmission of power to the sewing machine. The succeeding cam step 121, however, does shift the latch finger 114 opposite the sleeve shoulder 108 to initiate the shortened coasting period.

From the foregoing description considered in connection with the accompanying drawings, the construction, manner of operation and several advantages of our automatic clamp-opener throw-out will be clearly and fully understood. It is apparent that the devices have a wide variety of uses, and it will be understood that the form, construction and arrangement of the several elements employed may be varied. Therefore, the privilege is reserved of resorting to all such legitimate changes therein as may be fairly embodied within the spirit and scope of the appended claims. I

Having thus set forth the nature of the invention, what I claim herein is:

1. In a cyclically operated sewing machine having a drive means and a stop motion mechanism for stopping said sewing machine at a definite predetermined'point in a sewing cycle, means for interrupting said drive means prior to said predetermined point comprising a control latch adapted to maintain said drive means in operative driving relation with said sewing machine, a plurality of latch releasing means operated by said sewing machine each being capable of tripping said latch to interrupt said drive means at a different interval prior to said predetermined point, and means rendering eiiective a selected one of said latch releasing means. a

Z. In a cyclically operated sewing machine, driving means therefor, a control member associated with said driving means and having a position effective to render said driving means operative and a position elfective to interrupt said driving means, a latch member movable in one direction to maintain said control member in a position in which said driving means are operative, means operated by said sewing machine for shifting said latch member in the opposite direction in a plurality of successiv-e increments during the operation of the sewing machine, and means for effecting movement of said control member to a position interrupting said driving means on any selected one of said plurality of successive increments of latch movement. i

3. In a cyclically operated sewing machine'having driving mechanism, means for interrupting said driving mechanism prior to completion of each cycle of machine operation, a work-gripping clamp and clamp-opening mechanism operated by said sewing machine, the combination of operator controlled mechanism for throwing said clamp-opening mechanisminto and out of operation, and means under control of said operator controlled mechanism for altering the timing of said interrupting means. a V

4-. In a cyclically operated sewing machine having driving mechanism, means for interrupting said driving mechanism prior to completion of each cycle of machine operation, a work-gripping clamp, and a clamp-opening mechanism operated by said sewing machine, means simultaneously rendering said clamp-opening mechanism inoperative and advancing the timing of said interrupting means. J 5 a 5. In a sewing machine having a driving mechanism, a stop-motion mechanism therefor, means for interrupting said driving mechanism to provide for a coasting period prior to operation of said stop-motion mechanism, normally inoperative mechanism appurtenant to said sewing machine, operating means adapted to harness the inertia of the sewing machine during said coasting period to operate said appurtenant mechanism, throw-out mechanism under control of the sewing machinev operator for rendering said operating means selectively operative or inoperative, and means under control of said throw-out mechanism for selectively varying said coasting period.

6. In a sewing machine having a work-gripping clamp, clamp-opening mechanism carried by said sewing machine, actuating means for said clamp-opening mechanism driven by said sewing machine, and a member movable bodily into and out of an operative position between said clamp-opening mechanism and said actuating means, a latch device carried by said sewing machine and adapted to engage and to lock said member into an inoperative position, and a manually operable latch-controlling lever carried by said sewing machine.

7. In a sewing machine having a work-gripping clamp, clamp-opening mechanism carried by said sewing machine including a clamp-opening push rod journaled therein, actuating means for said clamp-opening mechanism including a cam driven by said sewing machine, a lever pivoted in said sewing machine and bodily movable lengthwise of its pivotal axis into and out of an operative position between said push rod and said actuating cam, and latch means under control of the sewing machine operator for locking said lever in an inoperative position lengthwise of its pivotal axis.

8. In a sewing machine having a work-gripping clamp, clamp-opening mechanism carried by said sewing machine, actuating means for said clamp-opening mechanism driven by said sewing machine, and operating lever carried by a fulcrum rod which is journaled for turning and for axial movements in said sewing machine, said lever and fulcrum rod being movable axially to shift said lever into or out of operative position between said clampopening mechanism and said actuating means, and clampopener throw-out means comprising a latch lever carried by said sewing machine and disposed to engage and lock said fulcrum rod in an axial position in which said operating lever is in inoperative position, and a manually operable member carried by the sewing machine for controlling said latch lever.

9. In a sewing machine including an actuating mechanism and a stop-motion mechanism having two extreme positions, one in which power is transmitted to the sewing machine actuating mechanism and one in which motion of the actuating mechanism is arrested and an intermediate position in which transmission of power is inter rupted but the actuating mechanism is free to coast, means for controlling said stop-motion mechanism comprising a keeper member operatively connected with said stopmotion mechanism and confined to movement on said sewing machine into any one of two extreme positions or an intermediate position cor-responding to the three positions of said stop-motion mechanism, a latch member shiftably supported on said sewing machine and disposed for movement into and out of the path of movement of said keeper member, latch shifting means associated with said sewing machine actuating mechanism, one of said stop-motion controlling members being provided with an element defining at least two differently dimensioned sets of stepped surfaces of which each step corresponds to one of said three stop-motion mechanism positions, and operator controlled mechanism on said sewing machine operatively connected to shift said element to present a selected one of said sets of surfaces for interengagement with th other of said stop-motion members.

10. In a sewing machine including an actuating mechanism and a stop-motion mechanism having two extreme positions, one in which power is transmitted to the sewing machine actuating mechanism and one in which motion of the actuating mechanism is arrested and an intermediate position in which transmission of power is interrupted but the actuating mechanism is free to coast, means for controlling said stop-motion mechanism comprising a keeper member operatively connected with said stop-mechanism and confined to movement on said sewing machine into any one of two extreme positions or an intermediate position corresponding to the three positions of said stop-motion mechanism, a latch member shiftably supported on said sewing machine and disposed for movement into and out of the path of movement of said keeper member, means associated with said sewing machine actuating mechanism and effective to shift said latch member in a plurality of substantially equal increments to a position out of operative engagement with said keeper member, an element carried by said keeper member and formed with at least two sets of stepped surfaces, each step corresponding to one of said three stopmotion mechanism positions, said element being shiftably supported with respect to said keeper member, operator controlled mechanism on said sewing machine operatively connected to position a selected one of said sets of stepped surfaces for traversal by said latch member, said sets of stepped surfaces differing as to the length along the path of traversal by said latch member of that surface corresponding to the intermediate or coasting position of the stop-motion mechanism, thereby providing for a selective variation of the number of increments of latch movement during which the sewing machine will coast.

11. In a sewing machine having an actuating mechanism and a stop-motion mechanism including a shiftable stop-motion frame having two extreme positions, one in which power is transmitted to the sewing machine actuating mechanism and one in which motion of the actuating mechanism is arrested and an intermediate position in which transmission of power is interrupted but the actuating mechanism is free to coast, means for controlling said stop motion frame to vary the coasting period comprising a slide rod journaled with respect to said sewing machine, operative connections between said slide rod and said stop-motion frame, a sleeve journaled for turning movement on said slide rod, means securing said sleeve against movement axially with respect to said slide rod, a plurality of sets of radially extending stepped latch surfaces formed on said sleeve, each of said surfaces corresponding to one of said stop-motion frame positions and each of said sets of surfaces differing in the radial dimension of at least one of said surfaces, a latch lever carried by said sewing machine, a latch finger carried by said lever and disposed to move in a path traversing radially of said sleeve, means under control of said sewing machine actuating mechanism for tripping said latch lever in a plurality of successive increments, and operator influenced means for turning said sleeve to position a selected one of said sets of stepped latch surfaces in the path of said latch finger.

12. In a sewing machine as set forth in claim 11, a work-gripping clamp, clamp-opening mechanism carried by said sewing machine, an operating means for said clamp-opening mechanism driven by said sewing machine actuating mechanism, a member movable bodily into and out of operative position between said clamp-opening mechanism and said operating means therefor, a latch device carried by said sewing machine and adapted to engage and to lock said member into an inoperative position, said latch device being under control of said operator influenced means for turning said sleeve.

13. In a cyclically operated sewing machine having a drive means, stop motion mechanism for stopping said sewing machine at a definite predetermined point in a sewing cycle, means for interrupting said drive means before the sewing machine reaches said predetermined point to provide a coasting period, mechanism for selectively advancing or retarding the point in the cycle at which said interrupting means is operated to vary the coasting period, and means under control of the sewing machine operator for actuating said mechanism.

References Cited in the file of this patent UNITED STATES PATENTS 1,843,534 Allen Feb. 2, 1932 2,721,526 Ivanko Oct. 25, 1955 2,722,184 Sweet Nov. 1, 1955 

